Related to MAKE 04, MakeShift
MakeShift 04: Vinnie Forgione's "Zeno of Elea" Honorable Mention
by William Lidwell
March 16, 2006
This is Vinny's third honorable mention for another excellent entry. The DEKA team comments: "An honorable mention goes to Mr. Forgione for his foot valve tube pump made out of pipe from a fence gate, since he actually built a scale-model prototype." Congratulation, Vinny!
I have to admit, this may not be my best idea, but here it goes. To make things even more difficult on myself, I had to assume that the broken-down tractor is needed after effective repairs could be made, so disassembly of transmission, rear differential, or engine was not desirable. The following solution basically consists of a large version of a well sampling tube and a donkey-powered treadmill.
The well sampling tube/pump is pretty simple. I have to assume that there is either a hacksaw or pipe cutter available to cut a section of tubing from one of the farm-gates on the metal barn. I can't tell from the picture available, but I'm assuming the gates are made from 1_" 19-gauge steel tubing, and are about 12 feet long. Approximate cutting points are illustrated in Figure 1.
Hopefully, none of the welds were blown throughout the tubing. If they have been, and the tube isn't watertight, some minor pipe patching may be required. I'm assuming that the welds are fine and the tube is watertight. The tube is to be fitted with a makeshift foot valve, made with some wood, and some 4 mil plastic as a flapper valve. The inner diameter of the tube is going to be approximately 1.652 inches. In my scale model version (not shown), I used a small tree branch, shoved it in the tube, marked and cut to fit so that a portion of branch is still outside the tube. This is to facilitate easy removal and replacement if needed. In the scale model, the branch was about 1 inch long, so I'm thinking in the full model, it should be about 3 inches long, but however long is fine, just as long as it can still be drilled out for water flow.
I'm not sure if it was because the small-scale model was so small, but I only could drill out the branch directly in the center, and very carefully, since I must have cracked a half a dozen branches when drilling. If you can drill it out like Figure 2b, it would be better, since it would prevent the 4 mil plastic flapper valve from being sucked through a big hole in the middle. I have to admit; rubber is a much better choice. If there is an extra inner tube from the tractor lying around, use that as valve material. I do not want to crack open the tractor tire, since it's a big pain in the neck, especially if he uses liquid ballast.
Now, a circular flap is cut from the black or clear 4 mil plastic, and secured to the end of the branch that will be inside the tube. To complete the construction, wrap the branch with 4 mil plastic before shoving it into the tube, and wrap some excess around the lip of the tube where it meets the outside, to provide a watertight seal.
Now you have a nice, 11-12 feet long, self-priming, foot valve pump. This can be constructed in less than a day, but trial and error may lead to a full day of construction time. Most of the time is devoted to construction of the treadmill. It's my only solution for powering the pump, since assuming that there is a gas-powered motor lying around would be only boring, but way too convenient. I almost wanted to assume that the greenhouse had electric vent fans installed, but I thought that might be pushing it.
The tread of the treadmill will be constructed using the 3 oak barrels, and in a very huge act of generosity, the seatbelts from the vehicle you are driving. The wooden slats that make oak barrels are tapered and curved, so I'm not sure how it's going to work, but in my head, it should work OK. Using the seatbelts in the vehicle you are in is a stretch, too, but I guess if it really were me, I'd swing through Tijuana on my way back to the States, and pick me up some new ones before CHiPs gives me a ticket _. Three-point seatbelts are about 140 inches in length, or about 11_ feet. One and a bit may be needed per side of the tract. In order to minimize the taper and curvature of the slats, we are only going to use the middle of the oak barrels, approximately 2 feet total or so. I have a half-barrel planter at home, and the top of my half-barrel, which is really the middle of the barrel where it was cut, is 3_ inches wide. About a foot down, it's about 3_ inches, so it's not too bad, and 2 feet wide of track should be enough for a donkey. The slats are not all the same width, so try to get as many the same size as possible. In order to have a tract length of about 5 feet, a total length of 15 feet is going to be needed, but actual measurements and tweaking will be needed on site. That translates to about 48 slats total. Since the barrels are dry, and therefore not watertight, the slats may just slip right out. If not, you'll have to break the metal bands off.
I'm hoping the farmer has a lot of washers and bolts laying around, because I'd rather use them to attach the seatbelts to the slats. If not, wood screws or nails may be used, with a possible wood/belt/wood sandwich to prevent the belt from tearing away. Full construction of the tract is held off until the roller units are ready.
Hopefully, the greenhouse has wooden tables, because I'd like to take apart the tables to use as a frame for the treadmill – 4 posts into the ground, plus bracing. Now, from looking on the Internet on how these treadmills were constructed, they had flywheel, to help the draft animal in doing the work. So, the front wheels need to be on a shaft that rotates. Drill holes large enough to fit some tubes from the farm gate, and slide wheels on and lock in place. If the wheels have set screws, great. If not, I'd really have to get my hands dirty and figure something out on site. Now, in Figure 1 it looks like the dividing tubes are smaller than the outside tube. I'd make holes in supports large enough to fit a section of large tube, and slide the smaller tube through. If some of the machinery has bearings that could do the job, fantastic as well. The rear wheels can rotate independently if needed. The key is not to break anything. I'd like to put everything back together, since all the machines available I think the family will need.
Now, to get everything to work together, arrange items as shown in Figure 7. You also want to line the streambed with the 4 mil plastic, all the way to the farm. This will alleviate some of the water seepage.
You are going to have to make a ramp for the donkey to get on the treadmill. The tube pump is attached to the outside of the flywheel, at a point to facilitate the pump to travel about 1 meter per revolution. If the inner diameter of the tube is 1.652 inches, here are the volume calculations:
So 1 meter of tube equals 1.383 liters of water. Now, to figure out how fast you need to push the donkeys, you need to figure out how much water you need to pump per minute in order to fill the requirement of 50,000 liters/day. Now, I read somewhere on the Internet (wish I could provide source), that a donkey can work labored for about 4 hours. We have 3 donkeys, so that's 12 hours – a donkey works 4 hours, is off for 8 hours. Now if you want to pump 24/7, fine, but I'm thinking just pump 12 hours a day. If only using 12 hours/day, you need to pump about 69.4 liters/minute. If around the clock, only 34.7 liters/minute. Since the tube is cycling up and down about 1 meter in rotation, you only need about 50 RPM for 12 hours of work, or 25 RPM for 24/7 rotation. The reason I'd go for the 12-hour shift is the pump should work better at higher RPM. Hope it works out!
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